Plasma etching systems and methods using empirical mode decomposition

A substrate etching system, comprising:

• an etching control module configured to selectively begin plasma etching of a substrate within an etching chamber;
• a normalization module configured to normalize a first wavelength of a first signal relative to a second wavelength of the first signal to produce a second signal including endpoint information and to output the second signal including endpoint information,
• wherein the first wavelength of the first signal includes endpoint information, and
• wherein the second wavelength of the first signal does not include endpoint information;
• a filtering module configured to, during the plasma etching of the substrate:
• receive the second signal including endpoint information;
• decompose the second signal using empirical mode decomposition (EMD);
• and
• generate a filtered signal based on results of the EMD;
• and
• an endpoint module configured to indicate when an endpoint of the plasma etching of the substrate has been reached based on the filtered signal,
• wherein the etching control module is further configured to end the plasma etching of the substrate in response to the indication that the endpoint of the plasma etching of the substrate has been reached.